The present invention generally relates to information signal recording discs recorded with information signals and a disc reproducing apparatuses therefor, and more particularly to an information signal recording disc which is recorded at predetermined positions thereof with an end signal for forcibly and automatically returning a reproducing element of a disc reproducing apparatus from a playing position to a rest position, and a disc reproducing apparatus for playing such an information recording disc.
Heretofore, attempts have been made to more effectively utilize information signals which are recorded on an information signal recording disc (hereinafter simply referred to as a disc). Such attempts include coupling to a disc reproducing apparatus an external device such as a microcomputer which has a discriminating function, for example, and controlling the disc reproducing apparatus by the external device. The control of the disc reproducing apparatus by the external device is carried out based on a control program which is recorded on the disc together with the information signals such as video and audio signals. As a result, it is possible to play the disc on the disc reproducing apparatus in the so-called interactive mode between the external device.
A signal recording system for recording the control program described above and a disc which is recorded with the control programs, are disclosed in a U.S. patent application Ser. No. 574,521 filed Jan. 27, 1984 in which the assignee is the same as the assignee of the present application. According to this previously proposed signal recording system, a modulated signal is obtained by modulating digital data related to the control program according to a self clock modulation system, such as the biphase space modulation system and the biphase mark modulation system, based on a reference clock having a period which is twice the horizontal scanning period of the video signal, for example. The modulated signal is then band-limited to the audio signal band, and is recorded independently on the disc or is multiplexed in time sequence with the audio signal and recorded on the disc.
On the other hand, a disc reproducing apparatus for playing the previously proposed disc described above, is disclosed in a U.S. patent application Ser. No. 574,520 filed Jan. 27, 1984 in which the assignee is the same as the assignee of the present application.
According to the previously proposed disc and disc reproducing apparatus, it is possible to simultaneously reproduce the video and audio signals, and the control program signal can also be reproduced from the track which is recorded with the video and audio signals. Accordingly, by successively processing the control program signal reproduced from the disc, it is possible to play the disc on the disc reproducing apparatus in the interactive mode between the external device.
However, the majority of the existing disc reproducing apparatuses are provided with functions such as high-speed reproduction and random search. The disc reproducing apparatus having the random search function, for example, is useful in that the operator may quickly search and find the information which is recorded at an arbitrary track position on the disc by carrying out the search with an arbitrary timing. But, when the random search is carried out when playing the disc which is recorded with the control program, the disc will be played in a manner which was not originally intended by the developer of the software who developed the control program, and the value of the program recorded on the disc will be lost. For example, in the case of a disc for use in a game in which the scene advances as the player (operator) increases his score, it will become possible for the player to see the scenes which will appear near the end of the game by carrying out the high-speed reproduction or random access, although the scenes which will appear near the end of the game should only be obtained depending on the skill and luck of the player. When anybody can easily see the scenes which will appear near the end of the game by carrying out the high-speed search or random access, without actually playing the game, there is a problem in that the player will lose interest in the game and the game will no longer be challenging and fun for the player.